抄録
We started research on Protein phosphatase (PPase), which dephosphorylates phosphoproteins, as a new food property-modifying enzyme. We searched for an enzyme that efficiently releases phosphate groups from milk casein and found an extracellular enzyme produced by Trichoderma virens. As a result of LC-MS/MS analysis of the purified enzyme, this enzyme was estimated to be an unidentified protein belonging to the acid phosphatase family. Characterization analysis showed maximum activity at pH5.6 and 50°C, suggesting that it could be applied to food products such as fermented milk. For the formulation of the enzymes, we attempted to maximize and stabilize enzyme activity by examining culture conditions and breeding. As a result, we finally achieved enzyme productivity 2,000 times higher than that of the wild-type strain, and thereby established it as a PPase preparation.
We obtained some application data for the developed PPase for food products. The PPase not only increased the number of bifidobacteria in yogurt, but also increased the amount of exopolysaccharides (EPS) produced by the Lactic acid bacteria, and changed the physical properties of the yogurt curd to be firmer and smoother. PPase-mediated dephosphorylation of milk casein is assumed to have a variety of effects on protein properties, leading to these results. In soy yogurt, it improved the viability of lactic acid bacteria and suppressed water separation, which is expected to contribute to improved product stabilization and preservation. It was also observed to improve the foaming properties of soy milk, confirming its various effects on food proteins. In the future, it is expected to be applied to various food products such as wheat, rice and plant-based foods.
